PHP SPL data structure encyclopedia: from beginner to expert

php editor Xiaoxin brings you "PHP SPL Data Structure Encyclopedia: From Beginner to Expert". This article will comprehensively introduce the various data structures in the PHP Standard Library (SPL), from basic knowledge to advanced applications, helping you master the skills of using data structures and become a professional PHP developer. Whether you are a beginner or an expert, you can gain practical knowledge and skills to improve your level in PHP development. Let's delve into the infinite possibilities brought by the PHP SPL data structure!

PHP Provides an affordable and feature-rich class library for common data types and operations: Spl. This article aims to provide both beginners and experts with a comprehensive overview of Spl data types, from basic to complex data types.

Basic data types

1. SplStack: A last-in-first-out (LIFO) stack.

$stack = new SplStack();
$stack->push(1);
$stack->push(2);
$stack->pop(); // 2
$stack->top(); // 1

2. SplQueue: A first-in-first-out (FIFO) linear data type.

$queue = new SplQueue();
$queue->enqueue(1);
$queue->enqueue(2);
$queue->pop(); // 1
$queue->top(); // 2

Complex data types

3. SplMinPriorityQueue: A collection of elements stored in the heap, where the elements are sorted according to their weight , providing the smallest weight to the element with the smallest Access rights.

$pq = new SplMinPriorityQueue();
$pq->insert(1, 1);
$pq->insert(2, 2);
$pq->top(); // 1
$pq->pop(); // 1

4. SplMaxPriorityQueue: A collection of elements stored in the heap, where the elements are ordered according to their weight, providing the smallest access rights to the element with the greatest weight.

$pq = new SplMaxPriorityQueue();
$pq->insert(1, 1);
$pq->insert(2, 2);
$pq->top(); // 2
$pq->pop(); // 2

5. SplObjectStorage: Store an object as a collection of values ​​using a set of keys.

$storage = new SplObjectStorage();
$object1 = new stdClass;
$object2 = new stdClass;
$storage->attach($object1, "value1");
$storage->attach($object2, "value2");

6. SplFixedArray: represents a fixed-length array.

$array = new SplFixedArray(10);
$array[0] = 1;
$array[1] = 2;

7. SplHash: A hash table that maps keys to values.

$hash = new SplHash();
$hash["key1"] = "value1";
$hash["key2"] = "value2";
$hash["key1"]; // "value1"

Advanced data types

8. SplArray: An enhanced array that provides support for multi-dimensional arrays, as well as methods for sorting and filtering values.

$array = new SplArray();
$array[0] = 1;
$array[1] = 2;
$array->sort(); // [1, 2]
$array->filter(function($value) { return $value % 2 == 0; }); // [2]

9. SplEnum: Represents a set of related constants to provide support for enumeration types.

class Colors extends SplEnum
{
const RED = "red";
const BLUE= "blue";
const Green = "green";
}
$color = Colors::RED;

Compare

type	Access Mode	Sort	filter
SplStack	LIFO	none	none
SplQueue	FIFO	none	none
SplMinPriorityQueue	heap	yes	none
SplMaxPriorityQueue	heap	yes	none
SplObjectStorage	Key value	none	none
SplFixedArray	Fixed length array	none	none
SplHash	Hash table	none	none
SplArray	Multidimensional Arrays	yes	yes
SplEnum	enumerate	none	none

applicability

The Spl data type is useful in the following scenarios:

• Manage complex data collections
• Implement data types such as stack, linked list and heap
• Operation object collection
• Storing metadata of data and objects

Extension

The Spl library can be extended to add new data types and operations. Please see the php manual for more details.

source

• PHP Manual
• Spl Data Structures in PHP

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